The 50th M.L.B. Draft Unfolds With a Surprise Factor

Unlike the made-for-television drafts in the N.B.A. and the N.F.L., there is still some mystery that surrounds Major League Baseball’s draft despite this being the 50th anniversary of the event. So when Rob Manfred, M.L.B.’s commissioner, walks to the dais Monday night to announce who the Arizona Diamondbacks have taken with the No. 1 pick, the selection will be a surprise to nearly everyone other than Manfred, the team and the player selected.

Among the complicating factors are that the format is relatively new (the draft was conducted by conference call until 2009), the players have had far less news media exposure than their counterparts in the other major sports, and teams occasionally choose a player who is not the consensus top talent because strategically they would rather distribute their assigned bonus pool to several players rather than one top talent.

This year, the player many believe deserves to be the No. 1 pick, Brendan Rogers, a high school shortstop, will be one of the four players expected to be in attendance at the draft. But others believe he will not be taken by the Diamondbacks.

Though Rogers is the rare shortstop who is strong defensively while projecting a middle-of-the-order bat, most mock drafts have Arizona taking Dansby Swanson, a shortstop from Vanderbilt. Swanson may not match Rogers’s potential in the field and at the plate, but he is considered closer to being ready for the major leagues and will most likely agree to a lower signing bonus.

Still, even Swanson is no safe bet to go No. 1. There have been plenty of surprises over the years. Stanford’s Mark Appel was the consensus top pick in 2012 when his hometown Houston Astros chose first, but the team took Carlos Correa, a 17-year-old shortstop from Puerto Rico in what many assumed was an attempt to save money. The next year, Appel was back in the draft with far less fanfare. He chose not to sign with the Pittsburgh Pirates, who had taken him with the No. 8 pick. The Astros reversed course and drafted him.

Proving that the instant reaction to picks, and where players rank, is not a science, Correa has developed into the one of the two or three best prospects in baseball, while Appel has struggled to a 5.74 earned run average in 38 starts over three minor league seasons.

Another complicating factor for the draft is how teams will react to the events that unfolded last year with the Astros’ selection of Brady Aiken. The first high school pitcher to be taken with the top pick since Brien Taylor in 1991, Aiken was unable to come to a contract agreement with the Astros, with the team reportedly concerned over problems with a magnetic resonance imaging test on his pitching elbow though Aiken insisted he was perfectly healthy.

Things ended poorly for the team and the player. Because the Astros had structured their offer to other players drafted based on the bonus pool available to them if they signed Aiken at a discount, they were unable to sign a few of their top picks, resulting in multiple grievances being filed. And Aiken, who was working out in hopes of entering this year’s draft as the top prospect, tore his ulnar collateral ligament and will enter this draft while recovering from Tommy John surgery.

Now both will get another chance. The Astros will have the No. 2 pick as compensation for not having signed Aiken, and Aiken may be taken in the first round, as some team is likely willing to gamble on his potential to make a full recovery.

Monday’s portion of the draft will include the first and second rounds as well as two competitive-balance rounds. The draft continues Tuesday with Rounds 3 through 10 and Wednesday with Rounds 11 through 40.

Joining Rogers in person at the draft will be Garrett Whitley, a high school outfielder, and the high school pitchers Ashe Russell and Mike Nikorak. While the potential is there for one of the players to endure a long wait before being selected, that player can take solace in the fact that Mike Trout, who attended the 2009 draft, had to wait until the 25th pick before his name was called. Things have turned out pretty well for Trout, the Los Angeles Angels outfielder and 2014 American League most valuable player.

A version of this article appears in print on , on Page D6 of the New York edition with the headline: The 50th Draft Unfolds With a Surprise Factor . Order Reprints | Today’s Paper | Subscribe